Condensation Particle Counters (CPCs) have different mechanisms to drain the working fluid out of the growth tube or wick. Most contemporary CPCs rely on gravity to drain the working fluid. However, as volumetric sample flow rates increase, any working fluid that drains in to the flow path has a tendency to create bubbles which then grow in to large particles that gets detected by an optical sensor within the CPC. Since these counts are generated internally to the CPC and are not caused by actual particles from a monitored environment, the internally-generated counts are considered “false-particle counts” and will occur even when the particle counter is sampling clean HEPA-filtered air. Performance of a CPC is rated by the number of false counts over a specified time period. For example, a semiconductor clean room may require less than six false counts per hour. Consequently, in general, the lower the number of false counts, the better the instrument. The disclosed subject matter discloses techniques and designs to reduce or eliminate false-particle counts in a CPC.